This was a song that Martin Winsor used to sing back in the 60s & 70s when I was going to the Troubadour in Old Brompton Road.   His interpretation was that the father was a warlock and the lad was climbing up the crag or wall to get to his girlfriend - the warlock's daughter.   When Martin sang it, the hairs used to stand up on the neck and the air trembled, but then, he was a bit unusual!

As far as I can recall, he used to substitute "roarin'" for "howlin'" in the third line of the chorus.   Otherwise the words seem much as he sang them.